1 / 25

Ecological Sustainability: what can models tell us?

Ecological Sustainability: what can models tell us?. CSCI 1210 Fall 2003 Note: please don’t forget the online student evaluations!. What is sustainability?. Humans living in a way that does not diminish Earth’s capacity to sustain life

amberly
Download Presentation

Ecological Sustainability: what can models tell us?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Ecological Sustainability:what can models tell us? CSCI 1210 Fall 2003 Note: please don’t forget the online student evaluations!

  2. What is sustainability? • Humans living in a way that does not diminish Earth’s capacity to sustain life • Alternatively: living within Earth’s ecological carrying capacity Are we going through a global ecological crisis?

  3. Overshoot and collapse • Previous model assumes carrying capacity is constant • What if a severe overshoot degrades the environment? • Carrying capacity might be permanently reduced • Image:http://www.dieoff.com/page80.htm

  4. Humans are different… • Human carrying capacity is hard to define, because… • Technological changes affect food production • Complex social factors affect population

  5. UN world population projections: • World population may have passed its inflection point in 1970. • Herman Kahn called this time TheYear Zero

  6. World3:The Nightmare Scenario • World3 model created by MIT systems group for the Club of Rome • Model updated, 1990 Graphic: www.dieoff.com

  7. Malthus in, Malthus out! • Nonrenewable resources run out… • Capital is diverted to resource extraction • Less capital for agriculture • Yields fall, leading to famine and death • Is this realistic??

  8. The Cornucopians • Economist Julian Simon bet ecologist Paul Ehrlich that prices of nonrenewable resources would fall • Ehrlich lost and had to pay Simon $1000 • Cornucopians argue that human ingenuity will surmount all “limits” to growth. http://www.cato.org/pubs/policy_report/cpr-20n2-1.html

  9. Are there limits? • Simon and climatologist Steven Schneider offered to bet Simon $1000 on each of 15 ecological indicators getting worse over time. • Simon declined this bet. • The limits to growth are not industrial resources, but ecological resources • The real limit may be the ability of Earth to absorb pollution

  10. World3 model and pollution • Here is what happens when you increase the initial stock of natural resources by 1000 times.

  11. World3 model and pollution • This time there is no shortage of agricultural inputs, but land fertility suffers because of pollution.

  12. The IPAT formula I = PAT Proposed by Paul Ehrlich • I = environmental Impact • P = population size • A = Affluence • T = Technology factor http://www.stanford.edu/group/CCB/Staff/paul.htm

  13. IPAT: a conceptual model • Population is not the only factor • An American has more environmental impact than a Bangladeshi or Chinese • To reduce environmental impact we must control P, A, T or all three • Problem with IPAT: no defined measure of total impact I

  14. Ecological Footprint model • Definition of total impact: • Ecological fooprint is the total land area that would be needed to support a city, country, or other population unit. http://www.ire.ubc.ca/ecoresearch/ecoftpr.html

  15. Results of Ecological footprint • Were everyone on Earth to live as an average North American… • It would require three Earths to sustain this lifestyle.

  16. World3 Persistent Pollution

  17. World3 pollution model • In World3, the world reacts to pollution problems after the pollution has already become a problem • Inevitable delays in inventing and deploying technology cause overshoot. • Pollution technology is modeled as a stock. You can add more technology but cannot make qualitative changes.

  18. Real-world pollution response • In order to avoid overshoot, societies try to deal with pollution problems before they become severe • In the long term, qualitative changes (redesigning technology) is more powerful than adding filters to the back end of the smokestack

  19. Ecological safety factor? • Many scientists believe that humans should use at most 50% of Earth’s ecological capacity • This gives us a safety margin in case our calculations are off • It also leaves some room for other living things to share our planet

  20. The Big Question: • How much do humans have to change in order to live within Earth’s carrying capacity?

  21. And the answer is… • Ecological overload factor if every Earthling comes up to US lifestyle: 3 • Additional population increase from 6 to 9 billion: 1.5 • Further improvement needed to leave 50% of Earth alone 2 TOTAL IMPROVEMENT NEEDED: 9

  22. What does this mean? • We need at least a 9-fold reduction in the amount of pollution caused by each dollar of economic activity • Design school: Factor Ten • Another design school: Zero Waste

  23. Is Zero Waste possible? • Nature does it! • Bill McDonough: divide materials into industrial nutrients and ecological nutrients • Recycle industrial nutrients • Compost biological nutrients • Voila! Future technology!

  24. A Democracy Deficit? • Those most vulnerable are far away… • And have little power to promote change • Needed: effective planetary democracy • Struggle over the global trade system – the front line of the battle to save the Earth?

  25. Acknowledgements • DOE vs EIA Hubbert curves: http://www.dieoff.org/page177.htm • Hubbert curves from http://www.hubbertpeak.com

More Related